Radiator fan stuck on full speed

EndyKwon · 01-04-2019, 06:52 PM

Both fans of my radiator turn on full speed as soon as I turn on the car. It could be 40F outside or 100F, it'll just be at max at all times. Every now and then I can hear the fan speed fluctuating down to like 80% speed, but I can't figure out what's causing it.

My coolant temp gauge shows normal temps, below the middle. I tried switching out the fan relay (PWM RAD FAN RELAY) and that didn't work either.

What else could be causing this?

I tried cycling the AC to see if it'll stop it.. nothing.

SouthArk370Z · 01-04-2019, 07:19 PM

First thing I'd do is check all the connectors in the circuit for looseness, corrosion, bent pins, etc. Connector and wiring harness locations (and much more) are in the FSM (link in sig).

EndyKwon · 01-04-2019, 07:29 PM

Quote:

Originally Posted by SouthArk370Z

First thing I'd do is check all the connectors in the circuit for looseness, corrosion, bent pins, etc. Connector and wiring harness locations (and much more) are in the FSM (link in sig).

I'll give it a good read right now. Thank you!

jwick · 01-04-2019, 07:34 PM

Did this just randomly occur? Did you get a tune recently?

My tune is setup up for 100% fan all the time.

EndyKwon · 01-07-2019, 02:39 PM

Quote:

Originally Posted by jwick

Did this just randomly occur? Did you get a tune recently?

My tune is setup up for 100% fan all the time.

No, it just came up out of nowhere. Car is 100% stock

Is it bad for the car to be at 100% fan? I mean, I'm sure the extra cooling will be nice in the summer..

FastZNuff · 02-13-2019, 12:39 PM

I am having this same issue going on with my car. It did it this morning and it was 34 degrees.. Lol. Would love to know if this is bad or not for the car!

mults · 02-13-2019, 12:46 PM

Fans will run if the A/C is turned on regardless of the outside temp...

fryzia23 · 02-13-2019, 05:04 PM

Fan control module most likely shorted. Usually this would be caused by stuck temp switch or relay but I believe our cars get the fan on/off switch straight from Ecu to the fan control at the fan shroud.

Nooree01 · 08-24-2019, 09:48 PM

Quote:

Originally Posted by fryzia23

Fan control module most likely shorted. Usually this would be caused by stuck temp switch or relay but I believe our cars get the fan on/off switch straight from Ecu to the fan control at the fan shroud.

Which temp switch are you talking about?
I am having the same problem and I know my ambient temps switch is bad

Sent from my SM-G975U using Tapatalk

fryzia23 · 08-24-2019, 10:02 PM

Our cars fan isn't switch controlled. The control module gets signal directly from ECU to turn on/off the fan based off of coolant temperature sensor. So if your temp on dash is correct then the ECU gets proper coolant temp. Faulty ambient temperature sensor would cause issues with heat or ac not functioning correctly. Nothing to do with radiator fan.

01-04-2019, 06:52 PM	#1 (permalink)
EndyKwon Enthusiast Member Join Date: Jan 2012 Location: Los Angeles Posts: 428 Drives: '11 BSilver Base 7AT Rep Power: 14	Radiator fan stuck on full speed Both fans of my radiator turn on full speed as soon as I turn on the car. It could be 40F outside or 100F, it'll just be at max at all times. Every now and then I can hear the fan speed fluctuating down to like 80% speed, but I can't figure out what's causing it. My coolant temp gauge shows normal temps, below the middle. I tried switching out the fan relay (PWM RAD FAN RELAY) and that didn't work either. What else could be causing this? I tried cycling the AC to see if it'll stop it.. nothing.

01-04-2019, 07:19 PM	#2 (permalink)
SouthArk370Z Premium Member Join Date: Nov 2010 Location: South Arkansas Posts: 8,435 Drives: 2014 Challenger Rep Power: 324198	First thing I'd do is check all the connectors in the circuit for looseness, corrosion, bent pins, etc. Connector and wiring harness locations (and much more) are in the FSM (link in sig). EndyKwon likes this. __________________ Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

01-04-2019, 07:34 PM	#4 (permalink)
jwick A True Z Fanatic Join Date: Dec 2010 Location: Houston Posts: 14,532 Drives: '10 G37 6MT Rep Power: 2465057	Did this just randomly occur? Did you get a tune recently? My tune is setup up for 100% fan all the time. elhombre likes this. __________________ '10 G37T 6MT Graphite/Graphite - BP - G37T Build

02-13-2019, 12:46 PM	#7 (permalink)
mults A True Z Fanatic Join Date: Aug 2011 Location: Cleveland, OH Age: 70 Posts: 1,830 Drives: 2010 (40th) #706 Rep Power: 16886	Fans will run if the A/C is turned on regardless of the outside temp... __________________ mults 40th Anniversary 'Z', 312.06HP/260.58TQ (Dynosty EcuTek Tune) Build Date/Number: 1/27/2010 #706 Berk HFC + CBE, R2C CAI, Clear Bra, Cleveland Z Club

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02-13-2019, 12:39 PM	#6 (permalink)
FastZNuff Base Member Join Date: May 2017 Location: California Posts: 8 Drives: 2014 370Z-SRS-M6 Rep Power: 8	I am having this same issue going on with my car. It did it this morning and it was 34 degrees.. Lol. Would love to know if this is bad or not for the car!

02-13-2019, 05:04 PM	#8 (permalink)
fryzia23 Enthusiast Member Join Date: Dec 2010 Location: new jersey Posts: 452 Drives: 2011 MB 370Z NISMO Rep Power: 1246	Fan control module most likely shorted. Usually this would be caused by stuck temp switch or relay but I believe our cars get the fan on/off switch straight from Ecu to the fan control at the fan shroud.

08-24-2019, 10:02 PM	#10 (permalink)
fryzia23 Enthusiast Member Join Date: Dec 2010 Location: new jersey Posts: 452 Drives: 2011 MB 370Z NISMO Rep Power: 1246	Our cars fan isn't switch controlled. The control module gets signal directly from ECU to turn on/off the fan based off of coolant temperature sensor. So if your temp on dash is correct then the ECU gets proper coolant temp. Faulty ambient temperature sensor would cause issues with heat or ac not functioning correctly. Nothing to do with radiator fan.